Agricultural vehicles such as tractors, combines and the like are commonly used in agricultural fields for a variety of jobs, and construction vehicles and other large work vehicles are used for many different jobs on a variety of ground surfaces. Typically, these vehicles have large wheels with tires on which the vehicles are supported on the ground. However, for improved traction, vehicle track-module systems (or “track modules” or “track-module apparatus”) are used in place of wheels with tires, and such track-module systems provide a much larger ground-surface engagement area supporting vehicle weight and tends to prevent vehicles from becoming bogged down in mud or other soft ground surfaces.
Among the challenges encountered in the use of vehicle track-module apparatus is the need to distribute the load supported by the track module among the various wheels. These loads are both static and dynamic and may change during operation of the vehicle. Loads change as the vehicle encounters uneven ground, as the vehicle turns and as the slope of the ground being traversed changes. Ideally, all wheels remain in contact with the ground through the endless belt and share a portion of the load at all times.
One track-module unit which is intended to distribute load relatively evenly is disclosed in U.S. Pat. No. 7,628,235 (Satzler et al.) owned by CLAAS Industrietechnik GmbH of Paderhorn, Germany. A vehicle track roller unit is disclosed which has at least one pivotable subframe and at least one further pivotable subframe, and each of the subframes rotatably accommodates at least one land wheel. At least one subframe is pivotably mounted on the vehicle, and the at least one further subframe is pivotably mounted on the at least one pivotable subframe.
Another vehicle track-module unit is disclosed in United States Published Patent Application No. 2013/0154345 (Schultz et al.) owned by CLAAS Selbstfahrende Erntemaschinen GmbH of Harsewinkel, Germany. A vehicle track unit is disclosed which has a plurality of supporting rollers arranged one behind the other in the direction of travel of the vehicle and around which a belt is wrapped. The rollers are adjusted by way of at least one actuator between a first configuration, in which all supporting rollers are loaded, and a second configuration, in which at least one outer roller of the supporting rollers is relieved. An energy source delivers drive energy required to adjust the configuration. An energy accumulator is charged by the drive energy source and connected to the actuator in order to provide the actuator with the drive energy required to adjust the configuration.
CLAAS also has its Lexion Terra Trac product line which includes configurations which are intended to address some of these challenges. However, none of these prior art systems includes all of the elements of the present invention and meets the needs as outlined above.